Fog..i carry the big can on solo canoe trips more as a security blanket than anything else,with no one to look over your shoulder in camp or on the portage it's just feels better to have something to even the odds--a bit--
if i had to use one on a bear i would fog the ground in front of the big guy covering my nose and mouth with my arm.also close one eye just before you shoot so if you get any blow back you will still have one good eye.